High temperature resistant coating for engine exhaust system

Abstract

The invention relates to a high temperature resistant coating for an engine exhaust system. The high temperature resistant coating is characterized by being prepared through at least one step by mixing the following raw materials in parts by weight: 10-80 parts of base materials, 10-80 parts of ceramic materials and 5-30 parts of low-temperature glass powder, wherein the base materials include 10-50 parts by weight of silicon sol and 0-30 parts by weight of aluminum sol; and the ceramic materials include at least one of quartz sand, aluminum oxide, silicon carbide, talcum powder, kaolin powder, mullite powder and mica powder.Compared with an organic silicon coating, the high temperature resistant coating disclosed by the invention has better high temperature resistance because the silicon sol or the mixture of the silicon sol and the aluminum sol is used as the base material in the raw materials; the high temperature resistant coating disclosed by the invention is compact in structure, can be used at a temperature higher than 600 DEG C, has the advantages of anti-corrosive properties, namely salt-fog resistance, acid resistance, and the like, higher rigidity and abrasion resistance because various raw materials are mixed in appropriate proportion and synergistically play a role; and the high temperature resistant coating is matched with an engine material in thermal expansion coefficient, has good temperature and denaturalization resistance and is particularly suitable for engine anticorrosion.

Description

technical field [0001] The invention relates to a high-temperature-resistant coating, which belongs to the technical field of chemical coatings. Background technique [0002] The exhaust system of a diesel or natural gas engine must continuously withstand temperature changes between high temperature to 800°C and low temperature to minus 40°C. The exhaust system includes exhaust pipes, exhaust manifolds and other components, which are generally made of cast iron and stainless steel. These iron parts are exposed to different temperatures and environments, especially in sea or coastal areas, where they are more vulnerable to the attack of chloride ions from salt spray, and are easily oxidized and rusted, resulting in shortened service life of the parts. Therefore, the exhaust system of the engine needs surface anti-corrosion treatment. The most direct method of anti-corrosion treatment is to spray anti-corrosion paint on the surface of engine parts. However, ordinary anti-cor...

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Problems solved by technology

However, ordinary anti-corrosion coatings use organic matter as the main component and cannot withstand baking at temperatures above 300°C.

Chinese patent application CN102140308 discloses "a new type of high-temperature-resistant coating", which is a silicone high-temperature-resistant coating with aluminum powder as the main filler. The main component of this coating is methyl or phenyl silicone resin. The following performances are good, but at higher temperatures, the silicone resin is prone to cracking, and the metal aluminum is prone to oxidation reactions, so it cannot be used for a long time at high temperatures above 600°C

There is another inorganic high-temperature coating with heat resistance above 1000°C (Modern Technical Ceramics, 2011, p. 39), which contains rare earth oxides, but its thermal expansion coefficient does not match the engine material, and it cannot withstand drastic changes in cold and heat, so it cannot be used in the engine. Anticorrosion

In addition, the thick coating of this kind of paint is very easy to crack in the process of extreme changes in cold and heat

Some high-temperature-resistant coatings based on inorganic materials cannot prevent the penetration of corrosive gases or liquids because the coating is not dense and has pores, and it still cannot completely prevent the exhaust system of the engine from corrosion

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